Systems and methods of detecting incorrect connections in a humidification system
Various control methods can indirectly determine incorrect connections between components in a respiratory therapy system. For example, incorrect connections can occur between a patient interface, a humidifier, and/or a gases source. The methods can indirectly detect if reverse flow conditions or other error conditions exist. A reverse flow condition can occur when gases flows in a direction different from an intended direction of flow. The methods can be implemented at the humidifier side, at the gases source side, or both.
1 . A reverse flow detector for a humidification system that includes a gases source, a humidifier, and a breathing circuit, and configured to detect a reverse flow condition in the humidification system, the reverse flow detector comprising:
a controller configured to:
receive a sensor signal indicative of an outlet temperature at an outlet of a chamber of the humidifier that carries humidification fluid; and
in response to detecting at least two trigger events related to the outlet temperature of the chamber, output an indication of a reverse flow condition,
wherein a first trigger event comprises the chamber outlet temperature reaching a first threshold temperature.
2 . The reverse flow detector of claim 1 , wherein the controller is configured to output the indication of the reverse flow condition further in response to detecting a pattern of the at least two trigger events.
3 . The reverse flow detector of claim 1 , wherein the controller is further configured to start or restart a timer in response to detecting a first one of the at least two trigger events.
4 . The reverse flow detector of claim 3 , wherein the controller is configured to restart the timer from a time when a trigger event was most recently detected.
5 . The reverse flow detector of claim 3 , wherein the controller is further configured to determine whether the timer has expired in response to no trigger event being detected.
6 . The reverse flow detector of claim 1 , wherein the controller is further configured to initiate a second method of detecting an indication of a reverse flow condition in response to outputting the indication of the reverse flow condition, and/or configured to be displayed on a user interface of the humidifier and/or the gases source.
7 . The reverse flow detector of claim 1 , wherein the controller is configured to output the indication of the reverse flow condition by activating an alarm, wherein the alarm is visual and/or audible.
8 . The reverse flow detector of claim 7 , wherein the alarm is activated only after a pre-determined operating time period has been reached.
9 . The reverse flow detector of claim 1 , wherein the first threshold temperature comprises a chamber outlet cut-out temperature.
10 . The reverse flow detector of claim 1 , wherein the first threshold temperature is one or more of above 37° C.; between 37.1° C. and 50° C.; between 38° C. and 45° C.; between 42° C. and 44° C.
11 . The reverse flow detector of claim 1 , wherein, in response to detecting a first one of the at least two trigger events, the controller is further configured to detect a subsequent one of the at least two trigger events only after the chamber outlet temperature has fallen below a second threshold temperature.
12 . The reverse flow detector of claim 11 , wherein the second threshold temperature is below the first threshold temperature and above a chamber outlet temperature setpoint.
13 . The reverse flow detector of claim 1 , wherein the detecting is performed during setup of the humidification system or just after setup is finished.
14 . The reverse flow detector of claim 1 , wherein the detecting is performed during steady state operation of the humidification system or by interrupting steady state operation for a period of time.
15 . The reverse flow detector of claim 2 , wherein the controller is configured to detect the pattern based on a predetermined periodicity of the at least two trigger events.
16 . A humidifier for a humidification system, wherein the humidifier comprises the reverse flow detector of claim 1 .
17 . The humidifier of claim 16 , wherein the controller is further configured to disable power to a heater plate of the humidifier and/or a heat source in an inspiratory conduit of the breathing circuit in response to outputting the indication of the reverse flow condition.
18 . The humidifier of claim 17 , comprising a safety feature configured to disable power to the heater plate of the humidifier and/or the heat source in the inspiratory conduit in response to outputting the indication of the reverse flow condition.
19 . The reverse flow detector of claim 1 , wherein the controller is further configured to detect a subsequent trigger event of the at least two trigger events, wherein the subsequent trigger event comprises the chamber outlet temperature reaching a third threshold temperature.
20 . The reverse flow detector of claim 19 , wherein the first threshold temperature and the third threshold temperature are the same.